A police officer said around noon, nearly 20 SNC members intercepted five trucks, in which a pay-loader machine and a few generator sets were being taken out of the factory through gate number five.

The vehicles belonged to the company that the Tatas had engaged to dismantle the machines and shift to other places.

The employees of the company, who were in the vehicles, requested the SNC members to let them go but they refused to budge. The protesters, who sat outside the factory gate, demanded that Ratan Tata should reconsider his decision to pull out from Singur.

After a few minutes, the trucks were taken back to the project area, as the SMC supporters blocked the factory gate for several hours.

A senior police officer said the Singur police went to the spot to pacify the protesters, but their request to withdraw the blockade was turned down by the SNC supporters.

SNC convener Sadai Koley said: “We want to make it clear that the Tatas will not be allowed to shift machines from the project area. We will allow only the entry of machines and not the exit. The Tatas will have to come back because almost 90 per cent work on the project is over.”